- Last Episode: The Big O 2 EP 10 (Sub) Full
- First Episode: The Big O 2 EP 1 DVD
* Script written by Konaka Chiaki.It is 40 years after an incident called "The Event" occurred, which destroyed the city of Paradigm and erased the memories of the citizens. Even though their lives eventually return back to normal, remembering the use of technology like electricity and vehicles, they are still plagued with the problem of not knowing what had exactly happened to them over 40 years ago.Roger Smith is known as the Negotiator, and he sees it as his duty to protect the people while he deals with his own mysterious past. His allies are; the android Dorothy, his butler Norman and a giant robot called the Big O.
- Other Title: The Big O, Big O Roger, Big O, THEビッグオー
- Status: Completed
- Sub/Dub: Anime Sub
- Anime Type: TV
- Genres: Action, Mecha, Mystery, Psychological, Sci-Fi, Animation, Drama, Action & Adventure, Android, Detective, Conspiracy, Angst, Dieselpunk, Loss Of Memory, Post-apocalyptic
- Characters: Rosewater, Angel, Smith, Roger, Wayneright, R. Dorothy, Burg, Norman
- Score: 7.53
- Rank: 1648
- Popularity: 2025